


Claude's Experiment

by MiliusPrime



Category: Claude von Riegan - Fandom, Fire Emblem, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Denial, Edging, F/M, Impregnation Kink, Mostly nonverbal Byleth, Overstimulation, PWP, Penis In Vagina Sex, Possessive Behavior, Subtle Dom/Sub, Teasing, Vaginal Fingering, Vaginal Sex
Language: English
Status: In-Progress
Published: 2019-08-04
Updated: 2019-09-03
Packaged: 2020-07-30 18:57:17
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 5
Words: 7,718
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20102032
Author URL: https://archiveofourown.org/users/MiliusPrime/pseuds/MiliusPrime
Summary: Claude comes up with an experiment to help Professor Byleth with her struggle to express her emotions. A one-on-one experiment behind closed doors.





	1. Stage One

**Author's Note:**

> Hello, this is my new ship, its great. Fire Emblem 3 houses is great, house Golden Deer is best house, thanks for coming to my TED talk.

“I’ve noticed something _ odd _ about you, Teach.”

Byleth would’ve jumped at the unexpected sound of Claude’s voice from the door of her room, but as usual she just slowly lifted her head from her book to look at him. With a sigh, she stood and crossed her arms.

“Hello Claude.” What was he doing here so late…? “What have you noticed?” 

“Most people have already realized by now that you’re a tough nut to crack. Nothing ever breaks through that icy facade of yours! In terms of composure you’re like a stone fortress.” 

Byleth nodded. That was true, of course. 

“Several people have probably decided you don’t experience human emotions the same way most people do - it’s uh, kind of rude, but I’d be lying if I didn’t see where they’re coming from. However…”

He paused, smirking as he leaned his weight against the door and crossed his arms, assuming a rather cocky pose as if he had just learned a really juicy secret. 

Byleth leaned closer, anticipating his next words. What had he found? He watched her so closely sometimes she swore he knew more about her than she did about herself, much to her irritation.

“I’ve never been one to take people at face value. Where I grew up, it was essential to uncover every hidden face before said face stabbed you in the back. _ Which _ is probably how I found out everybody’s actually _ totally _ wrong about you.” He strode forward confidently, kicking the door shut behind him with one leg, and pointed almost accusingly at her.

“You are a completely normal person who feels just the same if not more emotion than the rest of us. Only problem is, you can’t show it.” He leaned closer. “Something in your body doesn’t let you. I’ve seen it. I see the look in your eyes sometimes as you struggle to react. You can only do it when the emotion is strong enough, can’t you?” 

His eyes searched her face smugly, _ very _ pleased with himself for seemingly figuring her out after such a long time being completely and utterly baffled. 

Byleth felt a mixture of anxiety and something else swell in her at how he seemed to stare right through her, and her face suddenly felt hot. Reluctantly, she raised her eyes to meet his and nodded.

“It’s… incredibly frustrating.” She admitted quietly, the slightest tinge of bitterness in her monotonous voice. She gritted her teeth. 

“To be completely honest with you, I… kind of feel like my body is only half mine.” _ And not just because I literally have a mystical 12 year old sharing it. _ She added silently. “It’s like… if I’m angry or sad I feel it normally but I have to… _ tug _ it upwards with all my might to show it. It’s so heavy. It’s exhausting.” 

Claude had leaned closer to her while she was talking, and a rapt expression had replaced his earlier smugness. It was both intimidating and made her want to keep going at the same time. She felt a thrill in her chest about baring her long kept secret to him. She felt vulnerable, it was new to her and her stomach flipped in excitement and nerves.

“Go on.” He urged her, thick brown brows drawn together, as if he almost didn’t dare breathe and ruin it. 

“... But sometimes when the feeling is strong enough the barrier? Just snaps and I’m free.” She bit her lip. “When I’m angry, it uh…” She gulped and lowered her eyes from his suddenly. 

“Nevermind.” She said, nervously, though her tone didn’t change.

“Oh _ no _ you don’t, Teach.” Claude stepped closer again, pressing into her space insistently and her back against the wall prevented her from backing any further away. “I’m not leaving here without the full and complete truth, not after how long and hard I worked to find this out. What were you going to say?”

“It feels... good.” She admitted, cheeks flushing a slight red from the embarrassment. “I can feel it sometimes in battle. I guess that’s why I like fighting so much…” 

After a moment of silence from him she gained her courage and peeked up at his face. 

He was looking at her with a completely new expression on his face she had never seen before - a dark intense glint in his eyes as he looked right into her, all mirth gone, replaced by something that made her stomach drop and heart beat faster.

“What? What is it?” She said uneasily.

“So what you’re telling me, is that it just needs to be intense enough for you to feel it.”

Byleth nodded, confused about where he was going with this and why he was looking at her like that.

“You’re in luck, Teach. I know just what to do to help you with that.”

For once, she was stunned into silence.

“That is, if you trust me?”

“Of course I trust you, Claude. But what did you have in mind?”

“I’m _ so _ glad you asked, Teach! Well first off, get comfortable.” He tugged at her armor pointedly.

Byleth already felt naked under his perceiving gaze, so with an internal shrug she got to work removing her metal armor. She felt him watching her as she kicked her boots off and after a moment’s hesitation turned the other way and shimmied her tights down and off her legs. She pondered for a moment and removed her leather belt that held her sheathe and carefully placed it down on the table beside her bed. This just left her in her simple black satin dress.

Turning back to her silent observer, “What now?” she asked slowly, recognizing the mischevious look in the schemer's eyes. Just what kind of game was he up to now? She'd play along for now.

“Let’s start with a simple trust test.”

“Oh? I already said I trusted you earlier.” 

“Oh I know, but I have to make sure. It’s essential for what I’m gonna do later. Promise!”

“Fine. But so help me Claude if you drop me, I’ll make you regret it. Don’t forget I’m your professor.”

Claude gasped and raised a hand to his chest theatrically. “You wound me, Teach! Would I ever do such a thing to my _ beloved _ Professor?” He accused, raising an eyebrow at her. “Now get over here. Or are you too chicken?”

She stared at him expressionless, her version of giving him an annoyed face. 

“Bawk bawk bawk… bawk!” 

“Fine.” She was so getting him back for that during their next training session. She would make sure it would involve chicken feathers in some way. She strode over to where he was standing and crossed her arms.

“A little closer now. Good. Now turn around.” _ Lots _ of chicken feathers. 

“Now, fall back! I’ll catch you.” 

After a moment of irritation at how she couldn’t possibly see how this would help her, she relented and leaned backward letting her body fall back.

There was a muffled thump as her body collided with his outstretched arms. But instead of pushing her back up, they instead wound tightly around her and dragged her back against his chest tightly.

“Got you.” Byleth scarcely had a chance to react to his deep voice whispering in her ear before one of his hands had a grip around her slender neck. “Now be a good girl and hold still for me.” 

Excitement burst through her veins. So he wanted to play _this_ kind of game. She could have easily escaped his grasp if she really wanted to, but she obeyed, heart racing as his other hand snaked under her clothes, brushing tantalizingly across her stomach, and then sliding lower, underneath the waistband of her panties. With a gasp she tried to jerk forward out of his reach, but Claude tightened his grip on her throat.

His fingers dipped down, brushing past her clit which sent a brief jolt of pleasure through her body, but he didn’t stop there, instead dipping down past her lips to her entrance. Her clit throbbed painfully in denied anticipation. Claude gave a low chuckle at the slick he found already seeping out, and gathered some of it, then pressed his wet fingers against her clit and rubbed the pads of his fingers against it in a slow circle.

“Claude!” Byleth whispered in shock at his boldness, throat going dry with exhilaration. They'd skirted this... attraction they felt for a while and she'd gotten used to him pushing the line enough to see her react, and then toeing it whenever it was about to go too far. Looks like that restraint went out the window now, though.

All she got in response was a sharp pain on the left side of her neck, and then the sensation of sensitive skin being sucked by warm lips. The fingers rubbing her clit pressed harder and sped up.

A small breathless moan of pleasure and arousal escaped her lips and on reflex she clamped her mouth shut.

“Tsk, now that won’t do. Open that pretty, smart, capable teaching mouth of yours so that I can learn from every sound you make.” The hand grasping her throat moved up to her mouth and pried her lips open to rest on her tongue. “Besides, I won’t stop until you’re screaming and crying out-” His voice dropped to a whisper right beside her ear, “-_ Please, Claude!” _

Byleth moaned around his fingers, her core tightening at his words. A pressure was building in her stomach as he relentlessly rubbed her now swollen clit, beginning to breathe shallowly as he picked up the pace. The sweet pressure of his fingers was almost unbearable but every time it was too much and she squirmed, he’d immediately restrain her hips. It was a never-ending assault of stimulation.

She wanted more. 

Byleth started grinding her hips up against his hand, silently urging him to go faster, but as if sensing her urgency, he kept the same infuriating pace that left her on the edge. 

“Want more?” Claude asked teasingly, all too knowing of her predicament. This was straight up teasing, and she wasn’t one to give up easily. “Hmm?”

She decided not to answer, wondering if she could wait out his patience.

However, after several minutes she was near tears. She was loathe to concede after showing such a bold face but she was at her limit, her walls clenched tightly every time his fingers pressed down and she was so aroused her slick had soaked through her panties and dribbled down her thigh. All she could think about was Claude, his voice, his breath in her ear, his hot body against her back, his strong grip, his rough fingers stroking her relentlessly. She’d long since stopped holding back her moans, whining and mewling in a torture of pleasure.

She wanted to come so bad. 

“Claude…”

“What’s up Teach? Need something?”

“I wanna… come…” She mumbled.

“What’s that? I don’t hear the magic word.”

“Please.” She whispered. She swore her face had never been redder in her entire life, she was so embarrassed. 

“Please, who?”

Goddess damn it all! 

“Please _ Claude _, let me come!”

“Hmm, it doesn’t really _ sound _ like you want t-”

“Please, please Claude let me come, please!” She begged, a near sob. His fingers rubbing away at her were almost painful in their pleasure.

“Well alright then, all you had to do was ask me nicely.” He said teasingly, only the slightest rasp to his voice alluding to the strain on his patience (and pants) he’d endured this whole time. 

His fingers pressed and rubbed on her abused nub, fast and hard and she swore she saw stars before her walls squeezed down hard as she came with a cry, shaking in his grasp as shocks of pleasure racked her body. 

For a long moment afterward the only sound was her labored breathing as she recovered. 

“...I’d like to officially announce Stage One of the experiment a success.” Claude broke the silence, withdrawing his hand from inside her clothes. 

“... Stage One? There’s not more, is there?” Byleth asked belatedly, turning around to face him a bit clumsily due to her legs feeling like they were made 99.9% of jelly. 

“What do you mean, of _ course _ there’s more!” Claude grinned upon seeing her flushed face, rumpled hair, and misty eyes, admiring his handiwork so far. “Someone like me doesn’t get famous for my genius plans for giving up at the first step.” 

She regarded him for a long moment.

“...What’s Stage Two?”

“Ah Teach, I am really _ so _ glad you asked.”

She yelped and grumbled as he suddenly picked her up and tossed her on her bed.

"Don't get cocky Von Riegan, remember I could fail you if I felt like it."

“You could... but stage two is where it _really_ gets interesting..."


	2. Stage Two

**Summary for the Chapter:**

> Claude's experiment continues, but doesn't go as planned.

Byleth usually had an impeccable command of every situation she found herself in, making sure to never leave herself vulnerable to attack. But maybe that statement needed a bit of revisement considering her current state - namely, naked, sitting in the lap of a half as naked shirtless Claude. 

Turns out Stage Two was a “test of her sensitivity” in the name of science. Claude had explained to her, in a matter-of-fact tone that this was again, completely necessary for the success of his experiment.

It was complete nonsense at this point, but considering the way his bare hands were firmly massaging the knots out of her neck and shoulders she couldn’t muster up enough resistance to move away. It was almost enough to forget that she was completely and utterly naked.

His hands found a particularly sensitive spot at the base of neck and she couldn’t help a pleased sound at the relief.

“Poor Teach, you’re so stiff. Not to be the guy who says “I told you so,” but this is what you get for not listening to us and overworking yourself all the time. Just look at this, I swear your muscles are tighter than the string on my bow!” He shook his head in mock dismay. “Guess I have no choice but to force you to relax.”

He slid his hands up her neck, then down her shoulders and arms, squeezing when he reached her wrists, then back up to her shoulders. This time, he moved them forwards, stroking her collarbone a few times, then moving them down her sides, fingertips grazing the sides of her bare breasts, lingering for a few moments, then following the curve of her waist and hips. 

Byleth shivered at the touch, slightly disappointed. She’d been sure he was about to touch her breasts… she’d be lying if she said she didn’t want him to. Though her room wasn’t cold, it wasn’t warm enough to be naked. At least, that was her excuse for the hard state of her stiff pink nipples.

After kneading at the soft skin at her hips for a few moments, Claude shifted his hands over to her stomach, pressing a line upwards slowly towards her hips. They paused when they reached the skin just below her rather ample breasts. 

Byleth held her breath.

She heard a shaky exhale behind her, and then gasped as Claude suddenly grasped both of her breasts with a squeeze. There was a hot jolt in her core as he fondled them, squeezing firmly as he moved his hands up and down. They were a bit too big for his hands to cup completely, but from the eagerness of his fingers now edging up to circle and poke at her nipples, he didn’t seem to mind.

“So stiff,” He remarked as he pinched both at the same time, pulling gently, “You cold, Teach? Or is it because of me?”

She shook her head vigorously, shyly glancing back at him. The normally nonchalant Golden Deer leader had such a non-characteristically intense look on his handsome face, as if _ she _ was the deer, and instead of being a hunter, he was a beast ready to devour her. She swallowed dryly and immediately averted her gaze.

“No? I see, they’re just stiff like the rest of your body. Don’t worry, I’ll make sure to relax all of you, thoroughly. After all, you’re always telling me not to cut corners in my work.” 

“You don’t have to do tha-aaat!” Byleth was cut off as he tugged sharply upwards and held there for several seconds before releasing. Claude chuckled behind her.

“Na-aaah!” She yelped as he did it again. She couldn’t see the look on the damned scheemer’s face but she was certain if she could there would be a big smug grin.

No doubt pleased with himself for eking out such noises from her, Claude repeated the action several times, til Byleth was breathless and that tell-tale ache had returned down there. Her nipples were now redder than pink, and they tingled and stung slightly.

“See, we’re making progress already. I’d say that was _ very _ expressive.” 

It had taken her no time at all to become hot and bothered, but her heart suddenly ached with the desire to turn and face him. He let her go at her squirming, curiously watching her as she shifted to face him. He met her gaze questioningly, and a moment passed before she pressed her lips together and decisively moved to sit on his lap and wrapped her arms around him, pressing her face into his chest. 

Claude was uncharacteristically silent, but she could hear his heart thundering in his chest. She got the feeling he was more comfortable being silly than serious, and maybe didn’t want anything serious with her. Her heart sank.

She was about to withdraw when she felt Claude’s hand on her cheek tipping her face up. In hindsight, she probably would have laughed at the odd, torn expression on his face. But right now all she could do was swallow thickly and bite her lip in a nervous hope that whatever options he was weighing resulted in her staying by his side. It was due to her being in that position that allowed her to see the exact moment something snapped within him as his eyes followed the movement of her lips. 

“Oh,” She gasped, squeezing her eyes shut as he abruptly surged forward and pressed his lips to hers, purposefully letting his momentum push her down to collide backwards on the bed with an “mmph!”

He kissed her almost as if he was trying to merge into her as much as possible - lips pressing insistently against hers, bare chest pressed down on bare chest, his hands clutching at her hair. Her heart felt like it burst into fireworks and she shook as she kissed him back, light-headed. 

The kiss grew in heat like a spreading open flame, Claude’s lips prying hers open aggressively. Not wanting to be outdone, in a moment of boldness she opened her mouth and snuck her tongue past his lips to brush against his. 

This earned her a very inappropriate sounding moan as he responded in kind, his tongue hot and in her mouth now. Claude gripped her waist with both hands and grinded his hips down hard against hers. Her enthusiastic keen was swallowed by the forceful kiss, and she clutched his back to grind back against him.

It was a bit sloppy but Byleth didn’t mind at all - in the small portion of her brain that wasn’t actively overwhelmed by excitement she was relieved. The less experienced Claude was, the less people he’d likely also kissed like this…

She drew back from his lips with a slight pop, panting, blushing a bit at the sound, to look at his face. Claude instinctively tried to follow her lips at first, but hung his head back for a moment to catch his breath. Byleth couldn’t help but find his usually composed handsome face - flushed an enticing red, his green eyes unfocused and pupils blown wide in desire - extremely arousing. She made a decision. 

“Forget the experiment.” She insisted breathlessly. "I want to do something else."

**Notes for the Chapter:**

> Sup guys here's the long awaited stage two :joy: which was originally gonna be the last chapter but somehow there's now probably gonna be a stage three and stage four. I'm not in control of these horny young adults anymore idek, send help.


	3. Stage Three

**Summary for the Chapter:**

> Claude tests Byleth's endurance.

“Take off your pants.”

Claude raised an eyebrow. “Wow Teach, how bold of you, demanding me to strip! That’s rather inappropriate you know, I should speak about this to- oww, oww! Okay sheesh no need to get _ physical _.” He rubbed where she had smacked his arm, mock pouting, but betrayed himself in the eagerness in which he unbuttoned and shoved his pants down, kicking them off haphazardly to land somewhere in her room. 

Byleth was about to encourage him to keep going, but paused for a moment as she looked at his boxers. The first thing she noticed was, obviously, the rather prominent bulge of his erection. The second however, was the artistically embroidered deer face (gold, of course) that aligned perfectly right in the middle which, complete with his erection, made the poor deer look like it’s nose had been stung by a bee.

Wordlessly, she reached over and dragged them down off his hips and flung them across the room. 

“Wha- hey! _ Rude_! Those are my favorite, I’ll have you know!” He huffed.

Byleth just rolled her eyes at him, eyeing - well, the one thing in the room she wouldn’t be able to look away from even if she wanted to - Claude’s bare cock, jutting up proudly from between his legs, the skin a few shades darker than the rest of his body. Not that she knew much about this sort of thing, but from what she did know he wasn’t much longer than average, but thicker than she had expected, like it would be weighty to the touch. Of course even Claude’s dick would be pretty. 

“Like what you see?” 

“It’s so… big.” She said, referring to how swollen it was, not really realizing what she said.

“My dear professor, flattery will get you-” He heaved her up on his lap ignoring her squeak of protest, “-_ thoroughly fucked _, like you deserve.”

Byleth blushed furiously at the unexpected filth that just came out Claude’s mouth, but offered no protest as his hands gripped her hips and dragged her forward and backwards along his cock, the hot velvety skin grinding against her clit and labia. Though his grip was to guide her hips, the unnecessary force with which he clutched her spoke to his possessive desire.

Byleth clung to his shoulders, exhaling heavily every time his now completely slick member slid back and forth against her. The steady wet friction against her clit felt good, and soon enough her arousal joined his to squelch lewdly every time she slid along his length. 

Claude halted her hips mid grind and rubbed the head of his dick teasingly against her entrance. 

“Time to test how long that stoic face lasts while you’re bouncing on my cock.” His flippant tone couldn’t hide his open greed as he pressed her hips downward, impaling her slowly but firmly til he was in to the hilt and held her there.

Byleth pressed her lips together and breathed through her nose, doing her best to relax around his member, feeling no pain thanks to their combined lubrication, but the strange feeling of the head of his dick pressing against something deep within her that she could only describe as _ odd _. A glance at Claude’s face, who was staring at the place between her legs were they were joined, told her he was seconds away from losing the incredible composure he’d held until now and she preemptively spread her legs wider considering the sake of her future self when he was done with her.

He forced a smirk at her and in an almost comically breathless flippant tone, challenged “Good luck holding yourself in,” and then mercilessly withdrew and thrust into her in slow sharp thrusts.

“Unhgh… hah… ah..?” His first two thrusts hurt as they brushed something sensitive within her, but after a few more, Byleth’s eyes widened in surprise as he hit that spot, it felt… good wasn’t the right word. More like, intense, or crazy, as if the back of her brain was tingling. 

He was probably trying to maintain perfect control but after several of his thrusts, they lost their sharp measured nature, and he panted against her neck as he fell into a more familiar constant up and down motion, his hands moving down from her hips to grasp her ass roughly with a growl. 

Byleth shuddered slightly at the force with which he was claiming her, leaning her forehead against the young man’s toned chest, enduring the intense mixture of sensations. That odd sensation when he hit something deep inside her felt good now, and she moved her hips in addition to his grip to take his cock harder. Her bare breasts bounced every met thrust.

After several minutes of rough fucking, Claude moved one of his hands from her hips to slide over her mound to rub hard on her clit as he continued to bounce her on his length relentlessly. Byleth’s hips stuttered and she moaned louder, her walls squeezing and clenching at the pleasure. 

“You’re so cute obediently falling to pieces on **my** lap.” Claude murmured in her ear. 

She was so aroused it was painful, her core tight and only the constant strokes of his hard member within her soothed her. She struggled to push her clit harder against his fingers, breath coming in short gasps and keening in pleasure with every stroke. She was completely encompassed by him and she felt like everything was rushing upward like her heart was going to burst. 

“You gonna come, Teach?” His eyes bore into hers, her lids heavy as she struggled against the rushing onslaught of pleasure. She just shook her head, frightened by the sudden intensity of emotions and sensations. She felt like she was about to snap. 

Sensing her distress, Claude wrapped an arm around her and pressed them chest to chest in a blazing hug that enveloped her and pressed his lips hard against hers. 

“It’s okay, just let go. I’ve got you. You’re mine.” Even breathless, his deep voice carried a reassuring warmth. He gritted his teeth and grunted as he thrust hard and deep inside of her. 

“Come. _ Now_, Byleth!” His impatient command rung in her ear and suddenly everything rushed forward at once and she gasped as her pleasure expanded and snapped and her walls clenched down, hard. Her mouth opened in a silent scream as she shuddered and writhed through several long pulses of pure ecstasy.

When it was over she slumped bonelessly against his chest, eyes closed as she struggled to regain her control. After she could breathe again, she made as if to get off his lap, but Claude’s grip tightened on her hips, keeping her hilted to the balls.

Leaning back, she noticed a hot trickling sensation and realized he had come too. He was watching the place they connected, a small frown on his face when he spotted the trickle of his come that had escaped her despite his efforts. 

He suddenly ground his pelvis into her and she squeaked, oversensitive, surprised to find that he was still hard within her despite having just came. He was a healthy young man in his prime after all, she supposed, but his stamina for this far outweighed hers.

“Again?” She protested, wriggling, to try and get out of his grasp.

Claude just pecked her on the lips and smiled, sweat slicking his wild curls to his forehead. “What do you mean, ‘again,’ Teach? I told you I was going to test your endurance until you were screaming out my name, didn’t I?”

“What-!?”

“Frankly, I’m hurt you doubted me for my word! Time for me to teach _ you _ a lesson for a change.”

Oh Goddess… what had she gotten herself into?

**Notes for the Chapter:**

> They asked for possessive, impregnation kink Claude and so who was I to deny them? Enjoy Claude's manipulative side that revels in controlling his most important asset. c:


	4. Stage Four

**Summary for the Chapter:**

> Claude read somewhere that women experiencing orgasms during sex increases the chance for a successful impregnation, so he's gotta test that in his experiment too.

Byleth painted heavily, her entire body covered in sweat. She was sure Claude had never seen her this disheveled, even in their most rigorous training sessions. She’d lost count of how many times she’d come now, the only thing she could think about was the hard pressure of Claude’s cock that relentlessly split her open, again and again. All she could feel was heat, pleasure, and the odd sensation of weightlessness that remained in her stomach and she could swear she was going to go crazy.

He’d given her a brief break to have her lie on her back as he had her hold her large breasts together as his shaft slid between them, though with their size, it was more like they formed a space that he moved in and out of, head occasionally peeking through at the top to kiss her clavicle. She’d been too tired to laugh at his flippant comment that he was the only one in the academy to fuck the best chest at the monastery.

Logically, she knew he had to have come himself at least twice, but he lost no vigor, callused fingers probing, his member exploring every inch of her on the inside. His green eyes seared into her, in their inexorable search of all her secrets, her entire self laid bare for him to break down and put back together at his whim.

She was so exhausted, but her traitorous walls still squeezed greedily yet down on him with every labored thrust. He rubbed and rubbed against her spot and she shook her head as if in denial of the crazy pleasure-pain of the overstimulation. 

“Just one more, Teach.” He murmured encouragingly, stroking the top of her head, the feeling of safety that came with his fingers against her fluffy blue locks a stark contrast to the free-falling feeling his hard shaft stoked in her with every motion.

She cried out hoarsely, with no hesitation now, the barrier that usually erected a stalwart wall between her and emotion nowhere to be found, and her overwhelmed cries filled her bedroom in a way she was sure she’d be mortified of had she the presence of mind to be.

_ “I can’t-I can’t-I cant-I caaannn’t!” _ Everything felt so hot and her clit tingled with as much pain as it did pleasure. Callused fingers stroked down her neck and over her chest, pinched and tweaked her already throbbing and red nipples and she groaned long and low. “ _ Oh- goddess- I’m!!” _

The dull pain and throbbing heat had suddenly snapped into pleasure, and within seconds she’d been wrenched up and over the peak again. 

Byleth shuddered and gasped, squeezing her eyes shut, resisting the ecstasy as it tore through her, stealing the last reserves of her energy. She came so sharply, everything felt numb. The pleasure stole it all from her and when it was over, she slumped back against the bed, boneless.

Claude slid out of her to save her the pain of more overstimulation and pressed a kiss to her sweaty forehead. “Good job.” 

He laid on his side next to her on the bed, pressing himself against her body gently, catching his own breath as he watched her, eyes lit up with pride. One hand stroked soothingly across her stomach, and if Byleth had the wherewithal to analyze the motion, she might have cracked a joke about whether or not he was imagining it large with child with how he was stroking. For now, instead of contemplating what schemes the young man could have up his sleeve, she just sank into the soft embrace of her bed and thought very seriously about never moving again.

“You gonna fall asleep on me?” He murmured, stroking her hair again, pressing her face against his chest in a protective gesture that contrasted with his never-serious tone. “I’m good with that.” 

The gentle tugging on her scalp felt incredible and she nestled herself closer into his body as the sweat on her body rapidly cooled her down. He hooked his leg around hers to shift the lower part of her body flush against him as well, and left it there rest on top of hers. She welcomed the heat and weight with a satisfied sound. Her entire body felt liquid and floaty from her many orgasms and it was easy to melt into a puddle of contentedness. 

She supposed she should be worried about the consequences having sex with one of her students - though the same age as her - would have. But it was hard to worry when Claude’s warm body enveloped her so, when his hand stroked her so tenderly. Hard to think anything could hurt her when his emerald gaze swept over her so determinedly. 

Byleth wasn’t sure how long she had dozed off for, but whenever she woke, Claude’s heat never left, the tempo of his heartbeat assuaging any fears. 

**Notes for the Chapter:**

> Claude, sticking his leggy out over Byleth: he protecc babby, and babby momma  
Byleth: bye im sleeping for 5 years
> 
> I'm sorry its short... I didn't think Byleth could withstand anymore so lets let her sleep a bit before stage five. :^)  
Imeanwhat there's a stage five???


	5. Stage Five

**Summary for the Chapter:**

> This experiment features what happens when Claude's oral fixation meets his hots for Teach. Or, how long does it take Claude to be useful with his smart mouth.

Had someone asked Byleth if the reason for her expressiveness the past week was because of all the secret looks she had been sharing with the flamboyant leader of the Golden Deer, she would have, of course, vehemently denied such a thing.

Despite it being completely and entirely true. She herself had been a bit shocked, anticipating regret, awkwardness… an inability to look each other in the eye, at least. Instead, it just whetted a longing in her that she’d been able to deny before, when she and Claude were just teacher and student, ally and ally. Of course, she was going to have to do something about the fact that every time her searching gaze met his, he felt the need to return it with a wink. Every. Single. Time. The smile that accompanied it was so different from his usual ones that he wore like a reflexive charm mask, in these, the happiness sparkled mischievously in his green eyes. 

And that sugar sweet squeezing in her chest was what she felt now, in the same classroom but just the two of them, and a locked door. Not that different of a situation, technically, but the small details that made it different had her pulse picking up.

Well, there were a few other things that were different as well. First off, she had her long layered locks up into a bun, a pair of clear lens circle glasses perched on her nose, her usual jacket off leaving her in her black turtleneck short-sleeved shirt. A short black pencil skirt replaced her usual shorts, and she had black pumps on instead of her usual high-heeled boots. Her lacy tights remained the same, at Claude’s behest.

Byleth didn’t usually use the long wooden pointer when she taught, preferring to just walk up and point to what she was referring to on the board - standing still for the whole lecture period always made her feel too restless, so she enjoyed the excuse to move around more. She had the pointer in hand now though, and the smooth glossy wood shone in the orange afternoon sun that cast long streaks into their classroom from the high arched window. 

Byleth used it to point to Claude now, who was dressed normally except his black and gold over-cloak was hung over the back of his seat, leaving him in his white cotton dress shirt, black flared trousers and boots as he usually was whenever it was a hot day. She resisted the urge to roll her eyes at the ridiculous expression on his face as he lowered his raised hand.

“Yes, Claude?”

“I have a question,” He announced, as if it wasn’t already obvious, “Professor Byleth.” He rolled the ‘b’ in his mouth with a pop. Byleth was still getting used to the oddness of him calling her anything other than “Teach,” but she supposed this was a bit more appropriate in this… scenario.

“... And I have an answer.” She said, with the slightest arch of one brow when he didn’t immediately respond. In a moment of inspiration, she tapped lightly on Claude’s throat with the wooden pointer, resting it against his adam’s apple for a few lingering seconds. 

Claude breathed out heavily through his nose and gulped hard enough for Byleth to see, a tinge of red in his cheeks. “Uhhh. I forgot my question.”

Byleth huffed out an amused breath. He was the one who wanted to enact this… roleplay? Fantasy? Thing, and yet, he was already losing track of his focus. She didn’t mind though - it was fun just to be near him and do something that he could enjoy.

“Anything I can do to help you remember? What were you last thinking about?” It was something she might have said under normal circumstances had a student forgotten a question, so she figured it was good enough for this.

“Woah, is there such a thing as double jeopardy here?” Claude laughed. “I’m_ sure _ you already know what’s on my mind.”

“Oh? I thought the only thing on your mind was schemes. Then… did it involve something like this?” Byleth asked, with her coy face - which only Claude could identify at this point considering it consisted only of her lip twisted just so - as she hiked a leg up and sat sideways on his desk. Claude watched the shift of fabric around her hips as she made herself comfortable with a hawklike expression.

He cracked a grin at her, “I’m pretty sure it qualifies as one and - yeah, that was the gist of it.”

“Doesn’t seem very school-appropriate, but…” She shifted herself further onto the middle of his desk, a leg on either side. 

“Don’t stop on my account, Teach - regardless of the subject matter, I’m ready to watch and learn.”

“Make sure you pay close attention, then.” Byleth said, and tapped under Claude’s chin with the pointer, drawing him up for a kiss.

She had intended to lead him into something soft and sensual, a tantalizing brush of lips to stoke the fire. And well, it had started that way. But maybe it stoked the fire a little too well, because her intentions went up in smoke as Claude’s lips got a little too hungry against hers.

“Claumph-” She tried to pull away and get back under control, but he chased her lips, enthusiastically swiping his tongue up against the swell of her bottom lip and then in against hers. Byleth felt her core tighten as her pulse picked up, and instead of continue to resist she tilted her head and pressed her mouth harder against his, meeting the wet heat of his tongue with her own.

Her mind went blank as they made out, only aware of Claude’s breath on her face, the insistent press of his lips against her, the tickling of his hair as an unruly brown lock flopped rebelliously out of place to tickle her forehead. Soon enough she could no longer stand the aching throb that grew in her core and reached for him, needing her hands on him, needing to feel him and press him closer to her.

“Ah!” Claude jerked away suddenly, breaking her out of her lustful haze.

“I got-... a little bit- carried away there-... ha ha.” He panted out. “Sorry, Teach.”

Byleth frowned and dragged the wooden pointer against the thin fabric of his shirt, down from his shoulder to his chest, making sure it passed over his nipple before circling it and pressing it in. She swallowed thickly at his involuntary shudder in response. 

“I’m afraid I’m going to have to give you an f.” She murmured, looking at where the pointer poked into the fabric for another moment before her eyes flicked back up to meet Claude’s.

“Aw really? C’mon, give me another chance. Isn’t there something I can do to get extra credit?” He leaned forward as he spoke, running his hands up her lacy thighs.

Byleth tried very hard not to think about how his hands seemed to span almost the entirety of them, and gently rapped the pointer on his knuckle in reproach.

Claude obediently withdrew his hands, though will no small bit of reluctance. 

“I know... you could give me a new test then.” There was something mischievous about the lift of his eyebrows. “How about an oral exam?”

Byleth’s mouth suddenly felt dry as she considered this.

“...Very well. Demonstrate your skills and I will correct you if necessary.”

No sooner had she assented than Claude’s deft fingers were pulling down her tights, but he slid them down her thighs slowly as he savored the sight of the silky black nylon peeling away to reveal smooth pale skin. When he was finished, he gripped her under her thighs and pulled her hips toward him, causing her to shift her weight, leaning back and resting back on her elbows. 

She felt him press the pads of two fingers against her covered mound, and a low chuckle from his throat. 

“Should have known your underthings would be black, too.” He explained at her inquisitive look, and took his time to explore the novelties of her black cotton panties before he hooked a finger around the fabric and pulled it aside. Byleth curled her fingers into a fist in anticipation as his breath fanned over her exposed labia, the air cooling it from the moisture that had already gathered there and glistened against the pale pink folds of her pussy.

“No hands.” She murmured breathlessly.

Claude pressed a kiss against the top of her thigh, barely an inch from where she wanted his lips most. “You sure? I know everyone says I have a silver tongue, but I’m pretty good with my hands too.”

“Yes. Now begin already.” She said impatiently.

The first swipe of his tongue was broad, long, and flat as he licked up from her leaking opening to her clit. He shifted forward in his seat to get closer to her, and repeated the motion with more pressure, this time sucking her labia gently into his mouth. Byleth’s clit throbbed painfully. 

He released her labia and pressed an open mouthed kiss against the top of her opening, tongue snaking up to wiggle itself in between her folds and Byleth tensed as the tip of his tongue brushed the bottom of her nub. He seemed determined to take his time exploring all of her as he swirled his tongue in a few circles around the outside of her clit, tiny jolts of pleasure whenever the side of his tongue brushed against it. 

This was worse than the worst possible kind of teasing.

“You’re… doing it wrong.” She said, when he didn’t seem in a rush to stop sating his curious tongue exploration of her sensitive parts.

“Gotta do the multiple choice before the long essay questions.” Claude’s voice was muffled from speaking from between her thighs, but Byleth didn’t need to see his face to know the mischievous expression she knew was there.

He seemed to get the message though, because before she could continue complaining, the wet heat of his tongue pressed against her clit, sliding back and forth wetly. 

The moan that came unbidden from her lips was more of a startled whine at the unexpected intensity of the pleasure, and Byleth couldn’t help but make more as Claude’s tongue flicked and slid against her clit with no break now. 

The wet friction was so perfect, Byleth couldn’t believe such a thing had existed for so long without her knowing about it. 

“That feels… so good!” She panted out, the muscles of her stomach trembling as the tightness in her abdomen grew faster than it ever had before.

She had no reason to believe he was exceptionally good at this, despite his claims -though she didn’t know his intimate history admittedly - but at this point it didn’t matter, because every lick, suck and kiss his pressed against her clit felt like heaven. Little gasps and moans of “ah!” filled the afternoon quiet in the classroom, and her mind felt hazy with lust and pleasure. 

A particularly hard suck had her core clenching and hips bucking, one slender hand winding itself into wild brown curls and pressing him against her harder.

Claude didn’t slow down, tongue and lips a constant steam of hot wet pleasure. Logically she knew that his tongue or jaw must have been sore by now, but he didn’t show any signs of trying to remove his head from between her thighs… and with every enthusiastic pass of his tongue against her throbbing nub, she was more inclined to be satisfied with that. Byleth was straight up leaking now, her slick dripping down past her other opening to make a small pool on Claude’s desk beneath her ass. 

The pleasure welled and expanded upward and Byleth’s eyes widened as her hips trembled, “C-Claude I’m… I’m gonna…!” She didn’t get out all of her warning, as her walls suddenly clenched and seized in the spasms of her orgasm. 

Claude licked her through it all, a muffled pleased-sounding moan from his throat at his success vibrating lightly against her. 

When the pleasure finally abated, Byleth released her grip on Claude’s hair and slumped weakly against his desk. Claude stood up and stretched his neck from side to side, a very self-satisfied smirk on his face. Her slick glistened around his nose, mouth, and jaw. 

“So, A plus?” His fingers carded through the blue bangs that clung to her sweaty forehead. 

“... B.” She breathed out when she caught her breath.

“N’awww really, just a B?”

“For the teasing.”

Claude barked out a laugh. “Touche. Alright, I can work with a B. I like that letter better anyways.” He said with a grin.

Byleth groaned. Goddess, she had barely had any time to enjoy the sweet floating relief of the afterglow before he’d had to open his big mouth and say something dumb.

“Get it? Cause Byleth starts with-”

“Yes, I get it.” She chucked the wooden pointer in his direction - unwilling to move just yet.

“Ooh, so violent!” Claude said after he ducked out of the way. “Takes more than this tongue to tame you for long, huh.”

“Doesn’t your jaw ever get tired?” Byleth complained half-heartedly as she reluctantly sat up and began to clean up their mess.

“Nope! Should have guessed that from the first day when I said I’d bend your ear with my talking.”

Byleth just rolled her eyes and began to search for wherever her tights had ended up - she couldn’t be seen in public without them.

**Notes for the Chapter:**

> Boy what that mouth do?


End file.
